.TH BUILDMAP 3X
.SH NAME
buildmap, transin, transout \(mi translate labels between computers
.SH SYNOPSIS
.nf
.PP
.B
#include <cbit.h>
.PP
.B "struct mapping *buildmap(int fd, char *file, char *me, char *pw, server);"
.PP
.B "transin(struct mapping *map, struct label *foreign, struct label *domestic);"
.PP
.B "transout(struct mapping *map, struct label *domestic, struct label *foreign);"
.fi
.SH DESCRIPTION
Buildmap and its partner (which may be another instance of
.IR buildmap )
at the far end of the stream 
.I fd
work out a mapping for translating labels.
The label space at the near end is defined by
.I file ,
which contains ASCII representations of
.IR cbit (3)
structures.
The identity (for authorization purposes)
of the near end
is
.IR me ,
using a secret password
.IR pw .
Each end challenges the other, using its own password to compose a
response, whose
validity is checked by
.I verify ;
see
.IR notary (3);
The ends need not know each other's passwords.
.I Server
is to simplify the protocol: one end should have server set to zero,
the other end to one.
.PP
.I Transout
and
.I transin
translate labels according to the formula
determined by
.IR buildmap .
Labels in transit are represented in the binary form of the source machine
and are translated on receipt, so
.IR transout 's
job is simpler.
Both routines
return 0 if translation is impossible or illegal,
otherwise they perform the translation and return 1.
.SH SEE ALSO
.IR cbit (3),
.IR notary (3)
.SH DIAGNOSTICS
These routines all return 0
on error.